Search results for "Spheres"
showing 10 items of 329 documents
High-Resolution Spectroscopy and Preliminary Global Analysis of C–H Stretching Vibrations of C2H4 in the 3000 and 6000 cm-1 Regions
2010
International audience; Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000 cm−1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030- 6250 cm−1 range with the use of a high resolution Bruker IFS 125HR Fourierspectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases. A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software…
“Hard” Sphere Behavior of “Soft”, Globular-like, Hyperbranched Polyglycerols – Extensive Molecular Hydrodynamic and Light Scattering Studies
2020
Whether or not hyperbranched polymers behave like quasi “hard spheres” in solution is the subject of numerous fundamental discussions, also motivated by research on the perfectly branched dendrimer...
Effects of gamma-irradiation on trehalose–hydroxyethylcellulose microspheres loaded with vancomycin
2003
Ionizing radiation can be used as a drug sterilization technique, provided that the drug itself is not modified and that no toxic products are produced; moreover, if the irradiated product is a drug delivery system, the drug release characteristics must not be significantly altered by radiation. The aim of this work was to study the effects of sterilization by ionizing radiation on hydroxyethylcellulose/trehalose spherical micromatrices, containing the antibiotic vancomycin. Our experimental results showed that gamma-rays did not alter the chromophore groups of vancomycin (UV measurements), and did not modify the kinetic behavior of drug release from microspheres. Moreover, no significant c…
Physico-chemical state influences in vitro release profile of curcumin from pectin beads
2014
International audience; Curcumin is a polyphenolic compound with diverse effects interesting to develop health benefit products but its formulation in functional foods or in food supplement is hampered by its poor water solubility and susceptibility to alkaline conditions, light, oxidation and heat. Encapsulation of curcumin could be a mean to overcome these difficulties. In this paper, curcumin was encapsulated by ionotropic gelation method in low methoxyl pectin beads associated with different surfactants: Solutol®, Transcutol® and sodium caseinate. After encapsulation, physico-chemical properties of encapsulated curcumin such as its solubility, physical state, tautomeric forms and encaps…
The antifibrotic potential of a sustained release formulation of a PDGF beta-receptor targeted rho kinase inhibitor
2019
Rho kinase activity in hepatic stellate cells (HSCs) is associated with activation, transformation and contraction of these cells, leading to extracellular matrix production and portal hypertension in liver cirrhosis. Inhibition of rho kinase activity can reduce these activities, but may also lead to side effects, for instance systemic hypotension. This can be circumvented by liver-specific delivery of a rho kinase inhibitor to effector cells. Therefore, we targeted the rho kinase inhibitor Y27632 to the key pathogenic cells in liver fibrosis, i.e. myofibroblasts including activated HSCs that highly express the PDGF beta-receptor, using the drug carrier pPB-MSA. This carrier consists of mou…
Self Calibrating Nano-Ruler
2012
The aim of a nanoruler is to measure distances on a length scale in the order of nanometers. This concept can be realized by two plasmonic nanoparticles (usually spheres), which are placed within a short distance to each other. Since the plasmon modes of both particles are coupled, they influence each other along the interparticle axis (i.e. longitudinal plasmon mode, resulting in a shift of the resonance wavelength compared to the single particle. Because the resulting resonance wavelength depends on the interparticle distance, the spectral investigation of such a dimer allows the determination of the interparticle distance.
The Hamburg/ESO R-process Enhanced Star survey (HERES):XI. The highly r-process-enhanced star CS 29497-004
2017
We report an abundance analysis for the highly r-process-enhanced (r-II) star CS 29497-004, a very metal-poor giant with Teff = 5013K and [Fe/H]=-2.85, whose nature was initially discovered in the course of the HERES project. Our analysis is based on high signal-to-noise, high-resolution (R~75000) VLT/UVES spectra and MARCS model atmospheres under the assumption of local thermodynamic equilibrium, and obtains abundance measurements for a total of 46 elements, 31 of which are neutron-capture elements. As is the case for the other 25 r-II stars currently known, the heavy-element abundance pattern of CS 29497-004 well-matches a scaled Solar System second peak r-process-element abundance patter…
Quantification of fluorescent dyes in organ tissue samples via HPLC analysis
2017
Abstract The determination of regional blood flow via the accumulation of fluorescent microspheres is a concept regularly used in medical research. Typically, the microbeads get extracted from the tissue of interest and are then quantified by measuring the absorption or fluorescence of the incorporated dyes without further separation from the medium. However, in that case the absorption spectra of different dyes can overlap when used simultaneously, leading to an overestimation of the concentration. Additionally, background absorption from the medium can be problematic. Therefore, a high performance liquid chromatography method for the simultaneous detection of four dyes (orange, crimson, y…
Interaction between Angiotensin Type 1, Type 2, and Mas Receptors to Regulate Adult Neurogenesis in the Brain Ventricular–Subventricular Zone
2019
The renin&ndash
A Hydrogel Based on a Polyaspartamide: Characterization and Evaluation of In-vivo Biocompatibility and Drug Release in the Rat
1997
Abstract This paper deals with the characterization of a new microparticulate hydrogel obtained by gamma irradiation of α,β-poly[N-(2-hydroxyethyl)-dl-aspartamide] (PHEA). When enzymatic digestion of PHEA hydrogel was evaluated using various concentrations of pepsin and α-chymotrypsin no degradation occurred within 24 h. In-vivo studies showed that this new material is biocompatible after oral administration to rats. PHEA hydrogel was also studied as a system for delivery of diflunisal, an anti-inflammatory drug. In-vitro release studies in simulated gastrointestinal juice (pH 1 or 6.8) showed that most of the drug was released at pH 6.8. In-vivo studies indicated that diflunisal-loaded PHE…